How to transfer ownership of car legally?

To prove ownership of a car, you need to be able to show proof of purchase like a receipt or other relevant documents if you have inherited the car (death or transfer of ownership). You can go to a solicitor to transfer a vehicle in someone else's name or you can use the V5/V5C document to transfer the ownership (for example, when you sell a car, you fill out section 3 of the logbook).